1. Field of the Invention
This invention relates to an image sensing device which is provided with an improved display system.
2. Description of the Prior Art
For the image sensing device of a video camera or the like, various methods have been contrived to continuously change the exposure time effected by a shutter or to continuously control the image sensing storing time such as in a camera tube. In carrying out image sensing, a device of this type permits fine control over the stored electric charge because the exposure time or storage time is continuously variable. However, in situations where such a photography parameter relative to image forming time is used in combination with other parameters, such as an aperture value, and the sensitivity of the image sensing device for better photography, the conventional image sensing device of this type has extremely poor operability. Furthermore, in order to continuously vary the image forming time, a complex control circuit is necessary. Furthermore, the read-out output from an image sensing device cannot be reproduced by an ordinary TV receiver unless a read-out driving operation is carried out in synchronization with a standard television period. Therefore, the continuous control over the exposure time or storing time (hereinafter the two will comprehensively be called the image forming time) necessitates a timing arrangement synchronized with the standard television period. However, it has been extremely difficult to synchronize image sensing device driving timing while continuously changing the image forming time.
Furthermore, in cases where various photography effects are to be obtained from a combination of different photography parameters such as an aperture value, exposure time, etc. as mentioned above, these photography parameters must necessarily be perceptible. However, it has hardly been possible to display the image sensing time, etc. without recourse to an extremely complex display arrangement. For example, when using the NTSC system camera, it is difficult to promptly determine an aperture value for apposite photography with an effected, display for example, "0.25 sec".
It is a general object of the present invention to provide an image sensing device which is capable of eliminating the above shortcomings of the prior art.
It is a more specific object of the invention to provide an image sensing device in which a display is readily observable and parameters such as image sensing time, etc. can be set and controlled without difficulty.
It is another object of the invention to provide an image sensing device and a method suited for obtaining an optimum photography effect using combinations of various parameters.
These and further objects and features of the invention will become apparent from the following detailed description of the preferred embodiments thereof taken in conjunction with the accompanying drawings.